Continuous filament formation



y 4 J. w. ALLQUIST ETAL 2,249,928

' cou'rmuous FILAMENT FORMATION Original Filed March 1 .8, 19:57

Jin /7//'0227 fllywsl OJ/far 0 gen/402m?) IN NTORS IBM ATTORNEYSPatented July 22, 1941 2,249,928 oonrrmoo os FILAMENT FORMATION JohnWilliam Allquist and Oskar Oppenlaender,

Rome, Ga., assignors to Tubize Chatillon Corporation, New York, N. Y., acorporation of Delaware Original application March 18, 1937, Serial No.131,598. Divided and this application October 18, 1938, Serial No.235,593

6 Claims.

This invention relates to spinning of artificial silk and the like andis concerned with opera tions in which a viscous liquid is extrudedthrough a small orifice in a spinnerette and immediately thereaftersolidified to form a filament. The invention contemplates improvementswhereby spinnerettes may be withdrawn from service temporarily forcleaning, testing, repairs, exchange, etc., without interrupting theformation of a continuous filament and therefore without interruption-tospinning or to the subsequent operations to which the spun filaments aresubjected. The invention may be employed to especially great advantagein processes of continu spinning, in which a strand of filaments isformed and subjected to all the customary treating operations to put itin marketable condition Without interruption of the continuity of thestrand.

This application is a division of our copending application Serial No.131,598, filed March 18, 1937, now Patent No. 2,198,448.

In several of the known processes for making artificial silk acellulosic spinning solution is forced through orifices in a spinneretteinto a setting or solidifying medium, which in the case of dry spinningis an evaporative atmosphere and in wet spinning is a coagulating bath,and is thereby solidified to form one or more filaments. The freshlyformed filaments are withdrawn continuously from the zone in whichsolidification occurs and passed to other operations such as, forexample, stretching, washing, desulphurizing, bleaching, drying,lubrication and twisting before the product is completed.

Conventional apparatus employed in the above-mentioned wet spinningoperation comprises an open tank to contain the coagulating bath, meansfor supporting the spinnerette below the surface of the bath, a conduitfor supplying spinning solution to the spinnerette, a metering pumpadapted to keep the solution flowing through the conduit at apredetermined and preferably uniform rate, and means for continuouslyWithdrawing the freshly formed filaments from the bath. Preferably theconduit to which the spinnerette is affixed is removably mounted so thatthe spinnerette can be withdrawn from the bath. Thus in one common typeof apparatus the spinnerette in spinning position discharges thesolution upwardly into the bath, and the conduit to which it is afixedis in the form of an S or a gooseneck which is bent through about 180 atits lower end and extends upwardly to a point above the top of the ofthe hollow bracket arms and is made tight by compressing the candlefilter inlet against said seat, but not so tight that the candle filtercannot be moved pivotally. When the spinnerette is to be withdrawn thecandle filter and gooseneck assembly are tilted to raise the spinneretteup out of the tank.

When the artificial silk industry was in its infancy it was customary tomake relatively coarse filaments, and a considerable lack of uniformityin filament size was tolerated. In consequence, orifices in spinneretteswere relatively large and clogging of the orifices and maintenance ofconstant flow rate through the spinnerettes did not present seriousproblems. It usually sufficed to clean the spinnerettes or to exchangethem for cleaned ones during the Weekend general shutdown which was thencustomary, and it was not necessary, except occasionally, to exchangethe spinnerettes at other times.

In more recent years, however, spinnerettes have required more care andattention. Several changed conditions have combined to bring this about.There has been a demand for finer filan'rents with consequent smallerorifices in spinnerettes and an increase in the tendency for orifices tobecome. clogged- It has become customary to introduce finely dividedsolid substances, such as pigments, into spinning solutions. Oversizeparticles or agglomerates of fine particles tend to lodge either in thespinnerette or in the candle filter which precedes it in the spinningassembly. It has become necessary to pay more attention to the rate atwhich solution is discharged from .the spinnerette in order to insuregreater uniformity in filament size.

Moreover, the weekly general shutdown which formerly afforded anopportunity to withdraw spinnerettes from service for testing,inspection, cleaning, exchange, etc., is no longer customary. Apparatusin the several operations of artificial silk manufacture has been so farimproved that a general shutdown of the entire plant for an overhaulingat fixed intervals is no longer required in commercial practice.

As a result of all these changed conditions, it has become customary towithdraw each spinnerette from its bath at fixed periodic intervals(ranging from a few hours to several days, depending upon the standardof excellence established for the particular artificial silk being made)and to inspect the condition of the orifices in the spinnerette byrubbing away the liquids with the thumb or with a dry soft piece ofcloth, paper, or the like. Thus, at relatively frequent intervals eachspinning operation is interrupted. The interruptions represent a wasteof material in the form of spinning solution and also of time consumedin threading the freshly coagulated filaments through the variousgodets, guides, rollers, and other guiding, tensioning and conveyingmechanisms which are associated with the spinning apparatus. This trainof guiding, tensioning, and conveying mechanisms provided for handlingthe fresh filaments is complicated. Each time that spinning isinterrupted and begun again, the filament ends must be threaded throughthe whole train, so that the time lost is considerable.

Continu spinning is conducted in such a way that as a continuousfilament is formed by extrusion and solidification of a spinningsolution, a portion of the same continuous filament which has beenformed earlier is being stretched, while other portions of the samecontinuous filament which have been formed still earlier are beingsubjected successively to other finishing operations such as washing,desulphurizing, bleaching, drying and twisting. In principle, continuspinning presents many outstanding advantages,

among them reduction in labor and increased efficiency of equipment, andthere is a tendency at present to adapt continu spinning on a largescale. There is, however, a very serious obstacle to such adoption.Freshly spun filaments are extremely delicate and tend to break easily.A broken strand of filaments in a process of continu spinning isdisastrous, usually necessitating an interruption of the entire train ofprocesses and a laborious and costly operation of starting up again.

From the foregoing, it will be clear that improvements are neededwhereby spinning interruptions and the resulting difficulties may beavoided. Moreover, it is highly desirable that the improvements be ofsuch character as not to necessitate the replacement or extensivealteration of present spinning equipment, which represents a largeinvestment. As a result of our investigations we have developedimprovements which substantially eliminate spinning interruptionsthrough inexpensive changes to present spinning equipment and in areliable manner.

In most artificial silk spinning operations, serious difficulties whichbring about interruption may be anticipated for the most part byobserving the surface conditions of the spinnerette and the character ofthe extruded material as it leaves the spinnerette. We have found thatin wet spinning operations the observation preferably is made through atube equip-ped with magnifying means, with one end submerged in the bathand its eye piece outside the coagulating bath. The space in the bathimmediately adjacent the spinnerette should be illuminated either with abeam of light entering the tank from outside or by means of a submergedlight. When such means are provided, it is relatively easy to anticipatedifiiculties that may cause spinning interruptions. It is seldom thatthe orifices in a spinnerette become clogged all at once or that otherchanges in spinning conditions occur suddenly. Usually there is agradual change in the size of one or more of the filaments at the pointof their formation or some other manifestation which serves as anindication of incipient spinning trouble. With a magnifying andilluminating unit (preferably portable) it is relatively easy to observethe surface condition of the spinnerette and of the filaments at thepoint of their formation at frequent intervals and thus determine when aspinnerette needs to be exchanged (instead of exchanging all of thespinnerettes at fixed intervals whether or not such exchange isnecessary). This has the effect of reducing considerably the frequencyof spinnerette replacement.

7 Freshly spun filaments attach themselves to each other if brought intocontact with each other. The greater the length of filaments in contactwith each other the firmer is the bond between them. The bondingtogether of the filaments may be due to the fact that they becomeentangled or entwined with each other, or to the fact that the filamentsare still plastic and stick or cohere to each other, or to both of thesecauses. In any event, the bonding which results permits the filamentsfrom one of a pair of neighboring parallel spinnerettes to be guidedover and attached to the filaments issuing from the other spinnerette.Upon this fact depends that feature of our invention wherebyspinnerettes may be withdrawn from a coagulating bath without spinninginterruptions. The stream of spinning solution forced through one of apair of substantially parallel spinnerettes placed close together in abath is continued while a stream of spinning solution is started throughthe second or auxiliary spinnerette. The stream from the secondspinnerette forms loose-ended filaments which are guided over until theyare in contact with the filaments issuing from the first or regularspinnerette. Preferably the contact between the filaments is lengthwiseand for a considerable distance and is made while the filaments arestill plastic. (A firm bond between the filaments from the twospinnerettes results, however, due to the entangling action alone.) Thespinning solution is eventually cut ofi completely from the first orregular spinnerette so that the spinnerette may be withdrawn from thebath, and the spinning of the filaments is taken up and continued on thesecond spinnerette. In this way there is no interruption of spinning torequire re-threading, when a spinnerette is withdrawn from the bath forinspection, testing, exchange, etc.

v The bundle or strand of filaments formed during the period whenspinning solution is being extruded from both spinnerettes is describedhereinafter as an interim product.

The foregoing process may be carried out with various types of apparatusas described and claimed in our copending application Serial No.131,598, filed March 18, 1937. The apparatus described hereinafter is,however, particularly useful, especially when it is desired to producean easily-identifiable interim product during the change-over periodfrom the regular spinnerette to the auxiliary spinnerette or vice versaand comprises a portable tank, a conduit communicating with the tank, aspinnerette attached to said conduit, valved means for introducing thespinning solution into the tank and means for forcing the solution fromthe tank through the conduit and the spinnerette. This apparatus iscombined with a regular spinning assembly and is adapted to operate inconjunction therewith. In the preferred form of the apparatus theportable tank is mounted on a horizontal rail or other conveying meansfor moving the tank and the accompanying auxiliary spinnerette along abattery of spinnerettes, and a metering device, such for example as aspin pump, is interposed in the conduit between the portable tank andthe spinnerette. The preferred form of apparatus also has the conduitfor spinning solution communicating with a lower portion of the tank andmeans for forcing gas under pressure into an upper portion of the tank,so that accumulated gas pressure will force the solution into theconduit.

Our invention, therefore, contemplates the combination (in rayonspinning apparatus of the continu type wherein a continuous filament maybe produced while a spinnerette is temporarily withdrawn from service)which comprises a first spinnerette, means for forcing spinning solutionthrough the first spinnerette, means for coagulating the solution thusejected from the first spinnerette to form a filament, means forinterrupting the flow of spinning solution through the firstspinnerette, a portable tank for spinning solution, a second spinnerettedisposable adjacent the first spinnerette and in substantial alignmenttherewith, a conduit connecting the portable tank to the secondspinnerette, means for forcing spinning solution from the tank throughthe second spinnerette and into contact with the coagulating means toform a second filament, means for guiding the first and second filamentsinto contact with each other, and means for interrupting the flow ofspinning solution from the second spinnerette. The foregoing combinationpreferably also includes a spin pump connected to the first spinnerette,a second spin pump mounted on the portable tank and a common drivingmeans for both spin pumps.

In operating the above-described apparatus, identification of theinterim product is facilitated by making it over-size. Over-sizefilaments may be produced by maintaining a full flow on the first orregular spinnerette for a short time after the auxiliary or secondspinnerette comes into operation, and the filaments from bothspinnerettes are joined. When changing from the auxiliary spinneretteback to the regular spinnerette a full flow is established on theregular spinnerette and after an appropriate interval, this fiow is thencut oif. The beginning and end of the interim product are thenidentifiable by the oversize portions, which may be caught later in anyof the subsequent steps of the process, with a knot or slub catcher. Ifnecessary, flow through the auxiliary spinnerette may be such that theentire interim product is over-sized, which permits the slub catcherinfallibly to detect and break off the interim product.

The maintenance of a full flow at the regular spinnerette duringchange-over is of advantage when filaments of fine denier are spun inthat the interim product is not so fine and delicate as to bring aboutaccidental breakage during change-over with consequent interruption.

It is also of advantage to produce an interim product of different coloras well as different size,

ratus of our invention is adapted to accomplish this result, although itmay be employed conveniently when it is not desired to produce aninterim product of different size or color. Our invention will be morethoroughly understood in the light of the following detailed descriptiontaken in conjunction with the accompanying drawing in which:

Fig. 1 is a diagrammatic side elevation (partly in section) of aspinning assembly arranged for the practice of our invention andprovided with an auxiliary spinnerette having a separate supply ofspinning solution; and

Fig. 2 is a partial end elevation of the apparatus of Fig. 1.

Referring now to Figs. 1 and 2, it will be seen that along a battery ofreguluar spin sets operating in a spin bath 6|, there is mounted ahorizontal slide rail 62. There may be a line of 100 or more suchregular spin sets in the same or different spin baths, each spin setbeing provided with a spinnerette 60A, a gooseneck 60B, a candle filter60C and a regular spin pump 63 and all being fed from a solution main 64disposed below and parallel to the sets. The slide rail preferably is Tshaped with the base of the T pointing toward the regular spin sets andwith a longitudinal axis of the rail lying parallel to the main. On therail, by means of a clip 65, is V mounted a horizontally disposedcylindrical tank 66 for an auxiliary supply 66A of spinning solution.The tank may be slid along the rail from spin set to spin set, or beremoved completely from the rail and carried to any desired position. Ifdesired, other transport means such as a wheeled carriage may beprovided for moving the tank from spin set to spin set.

An auxiliary spin pump 6! is mounted on the top of the tank and providedwith a gear 67a which can be dropped into mesh on a driving gear 68 ofthe regular spin pump. Spinning solution is moved out of the tank 66 bymeans of a pipe 69 communicating with the inlet of the spin pump andextending into a well 10 in the bottom of the tank. On the outlet of theauxiliary spin pump is fastened an auxiliary spinning assemblycomprising a candle filter 1!, an extra long gooseneck 12 and aspinnerette 13.

Preferably, the auxiliary spinning assembly and the auxiliary spin pumpare mounted pivotally on a swivel bracket 14 fastened to the top of thetank so that the spinning assembly can be tilted up out of the spin bathand the gear of the auxiliary spin pump can be swung up out of contactwith the driving gear.

The swivel bracket 74 comprises a base plate 15 which rests on the tankand three uprights thus facilitating its identification. The appa- 7 16,H, 18 formed integrallywith the base. The pipe 69 extends upwardly tothe upright 18 which has a bore 19 through which the spinning solutionrises. The bore communicates with a shout horizontal pipe which isjournalled in the upright 19 and is attached to the spin pump. Ahorizontal set screw BI is threaded in the upright 18 and bears againstthe end of the pipe 80. The pipe 80 in. the upright 18 forms a swiveljoint which may be tightened by the set screw, or released to permit thegear 61a to be disengaged from the driving gear 63.

The outlet of the spin pump 61 communicates with a short pipe 82 whichpasses through a journal in the upright 11 and is seated in the side ofa second shout pipe 83, and communicates with this pipe througha channelin the seat. The short pipe 8 3 is attached to' the candle filter H. Theother side of the short pipe has a blind seat in which an axle 84 isdisposed. This axle is journalled in .the upright 16 and a set screw 84Ais provided for forcing the axle into the seat. This set screw may beemployed to regulate the swivel joint formed by the seats in the pipe 83and the members 32 and 84.

The tank 66 is provided with a valved inlet 85 for spin solution inwhich may be included a distinguishing dye or other coloring matter. Theinlet may be at any convenient point, and for example, may communicatewith the tank through the well 10.

The tank has a gas inlet at a point near its top. The gas inlet isprovided with a valve 86 and a pressure gauge 81.

The operation of the apparatus of Figs. 1 and 2 is as follows:

The tank 65 is filled with an appropriate spin solution, such as onecontaining a distinguishing dye, and the apparatusis moved to aconvenient position on the rail adjacent a regular spinnerette which isto be taken out of service. Compressed air or other gas is forced intothe tank so that the somewhat viscous spinning solution tends to flow upthe pipe $9 to the auxiliary spin pump. Air may be admitted eitherintermittently or continuously, but because of the viscous character ofthe spinning solution the use of gas pressure to force solution up tothe auxiliary spin pump is strongly recommended.

The gear BTA on the auxiliary spin pump is then swung down intoengagement with the driving gear 68 so that solution is pumped .to theauxiliary spinnerette 73 from the tank. The auxiliary spinnerette isthen swung down into the spin bath at a point adjacent the spinnerettewhich is to be taken out of service. Filaments are formed at theauxiliary spinnerette and these filaments are guided over with a rod 9'0or the like until they attach themselves to the filaments issuing fromthe regular spinnerette. When a sufficient length of filaments hasattached the formation of filaments at the regular spinnerette isinterrupted, for example, by closing a valve (not shown) between thesolution main 64 and the regular spin pump 63, or by withdrawing theregularspinnerette from the trough and swinging the pump 63 out ofengagement with the driving gear 68. Repairs to or replacing of theregular spin pump or the regular spinning assembly may then be made.Thereafter, with the regular spinning assembly in good order and backinto spinning position, formation of filaments at the regularspinnerette is resumed; these filaments are guided so as to attachthemselves to the interim product; a firm bond is permitted to form andthen the flow of solution to the auxiliary spinnerette is interrupted bytilting it out of the bath trough and disengaging the gears 61A and E8.The apparatus may then be moved to another regular spinnerette and theprocess repeated.

As shown in Figs. 1 and 2, the auxiliary spin pump and theauxiliarygooseneck are swivelly mounted in the bracket, solutionbeingsupplied to the spin pump andltaken from the spin pump to the near endof the auxiliary spinning assembly through the hollow axles or pipes. Ifdesired, the auxiliary spin pump may be omitted, in which case solutionis fed from'the riser pipe 69 through a hollow axle of the bracketdirectly into the auxiliary spinning assembly. In such case it isconvenient to provide a valve at some point between the pipe 69 and theauxiliary spinnerette so that the flow of solution from the tank 66 canbe controlled.

By eliminating the auxiliary spin pump, the apparatus is considerablysimplified. However, such elimination makes it difficult to control andto maintain uniform the delivery of spinning solution through theauxiliary spinning assembly and the resulting character of the extrudedinterim product. We prefer, therefore, to use an auxiliary metering pumpin connection with the auxiliary spinning assembly as shown.

We claim:

1. In rayon spinning apparatus of the continu type wherein a continuousfilament may be produced while a spinnerette is temporarily withdrawnfrom service, the combination which comprises a first spinnerette, meansfor forcing a spinning solution to eject through the first spinnerette,means for coagulating the solution thus ejected from the firstspinnerette to form a filament, means for interrupting the flow ofspinning solution through the first spinnerette, a portable tank for asecond supply of spinning solution, a second spinnerette disposableadjacent the first spinnerette and in substantial alignment therewith, aconduit connecting the portable tank to the second spinnerette, meansfor forcing spinning solution from the tank through the secondspinnerette and into contact with the coagulating means to form a secondfilament, means for guiding the first and second filaments into contactwith each other, and means for interrupting the flow of spinningsolution from the second spinnerette.

2. Apparatus according to claim 1 in which a battery of firstspinnerettes are disposed substantially side by side in contact with themeans for coagulating the solution, and means are provided for movingthe portable tank and the second spinnerette along said battery.

3. Apparatus according to claim 1 having a spin pump for forcing spinsolution through the first spinnerette and a second spin pump forforcing solution through the second spinnerette, a common means fordriving both spin pumps, means for disengaging the first spin pump fromthe driving means, and means for disengaging the second spin pump fromthe driving means.

4. Apparatus according to claim 1 in which the conduit connecting thesecond spinnerette and the portable tank is swivelly mounted on the tankand a swivel mounting is provided for the first spinnerette.

5. Apparatus according to claim 1 having a spin pump for forcingspinning solution through the first spinnerette, a second spin pump forforcing solution through the second spinnerette, said second spin pumpbeing mounted on the portable tank, both spinerettes being swivellymounted.

6. Apparatus according to claim 1 having a spin pump for forcingspinning solution through the first spinerette, a second spin pumpmounted a on a portable tank for forcing solution through the secondspinnerette, a common driving gear for both spin pumps, a gear on thesecond spin pump adapted to engage the driving gear, and

means for disengaging the gear on the second spin pump from the drivinggear, both spinnerettes being swivelly mounted so that they may bewithdrawn from the coagulating means.

OSKAR OPPENLAENDER. JOHN WILLIAM ALLQUIST.

